Discussion
The following contains material that
requires more critical analysis but is a starting point for discussion.
Reasons why I believe that this technique will
in time, lead a reduced cost per ton to bale.
Potential output from realistic improvements to the loading, tieing
and bale extraction techniques. The resulting costs reflect the
difference in volume from less than a days work to several days
work.
| Product |
No. bales / hour |
Avg kg / bale |
Tons / hour |
Cost / T
@ $200 / hour |
Cost / T
@ $150 / hour |
| Newsprint |
6 |
1400 |
8.4 |
24 |
18 |
| Cardboard |
4 |
1250 |
5 |
40 |
30 |
| Soft plastic |
4 |
1300 |
5.2 |
38.5 |
29 |
| Tyres |
3 |
2000 |
6 |
33 |
25 |
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This is based on current hydraulic speeds. Increased hydraulic
speed is quite basic but to benefit would require improved loading
techniques that are at this stage quite difficult to envisage.
Other reasons leading to reduced cost.
Reduced energy requirement because pressure peaks on average
just two times per bale ie. one pressure peak per 600kg.
Squeezing from both ends introduces significant new pressures
over and above the friction losses of pressing from one end.
In a large centralized stationery baling operation, the cost
of delivering and operating the facility could be as much as the
baling cost.

Compacting tyres
The red area compacted to just 12 bales
Discussion
To appreciate the advantage of this technique, you need to understand
what happens with the traditional technique with the plunger and
either, the friction chamber or fixed chamber. As the feed rate
increases, (speed/slice size) there is a disproportionate increase
in energy requirement, maintenance requirement as well as reduced
density performance.
With the X Press technique of squeezing from both ends, we can
see that maximum initial pressures reaching the opposing platen
are at best 60-65% but often as low as 40-50% but more importantly
what we also see is a time factor. Even in the most crushable
materials like cardboard, through the final stages of density
increase, there is increasing resistance to speed.
Static pressure (sustained pressure) is more effective in all
materials (to varying degrees) than the more dynamic and indirect
pressures of the traditional plunger and friction chamber.
I have no hard evidence to support whether speed is a big effect
or a small effect. The greater the direct pressure, the greater
the indirect pressure via chamber friction. It is particularly
noticeable on a bale that has been left in over night.
Bigger slice size means more opportunity for material to move
into areas of less resistance during the compression period. Generally,
if material is compressed lengthways only;
- Density will be more even.
- The bale will only want to grow lengthways
- There will be fewer bulges.
However, this will be dependent on initial material having a
relatively mixed orientation (ie not stratified / layers) this
will always be a problem and simply requires better preparation.
Reduced maintenance/increased life expectancy has more to do
with the stresses resulting from pressure increase/decrease on
hydraulic equipment and construction than any other connection
to output.
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